Methods of electrophoretic analysis for goitrogenic indolic glucosinolates are being improved to permit rapid detection of glucobrassicin, neoglucobrassicin and 1-sulfonoglucobrassicin in a variety of foods and fodders from the Cruciferae (cabbage family) and related plant groups. Routes of biosynthesis, particularly the origin and insertion of the sulfur atoms in these compounds will be sought using the woad plant which is an unusually rich source of all three substances. The steps and conditions under which the sulfur is released as the thyroid-active thiocyanate ion will be followed. Results should be useful in assessing the importance of natural thyroid depressants of this type in common foods often forming a large part of the diet of those on a limited income, and will have theoretical interest in understanding sulfur transfer, rearrangement and oxidation reactions and the extent to which oxime metabolism contributes to this.